Abstract:To identify and analyze the promoter region of the gene aziU1 (PaziU1) in Streptomyces sahachiroi ATCC33158,the 183 bp DNA fragment upstream of aziU1 and the strong constitutive promoter PermE* (as the positive control) were cloned into the promoter-probe vector pIJ8660.The enhanced green fluorescent protein gene (egfp) was used as a qualitative and quantitative reporter of gene expression driven by the cloned promoters,PaziU1 and PermE*,with fluorescent intensity assay of mycelia.PaziU1 exhibited high level of promoter activities in three streptomycetes,Streptomyces sahachiroi,Streptomyces lividans ZX1 and Streptomyces albus.In the early growth phase (up to 36 h),the activities of PaziU1 were a little bit lower than those of PermE*.However,by 48 h,the activities of PaziU1 equaled and even exceeded those of PermE*.Therefore, that PaziU1 cloned from S.sahachiroi was identified as a strong constitutive promoter the same as PermE*.